Precision gauge unification from extra Yukawa couplings

We study the theoretical and phenomenological consequences of modifying the Kähler potential of the MSSM two Higgs doublet sector. Such modifications naturally arise when the Higgs sector mixes with a quasi-hidden conformal sector, as in some F-theory GUT models. In the Delta-deformed Supersymmetric Standard Model (DSSM), the Higgs fields are operators with non-trivial scaling dimension 1 < ∆ < 2. The Kähler metric is singular at the origin of field space due to the presence of quasi-hidden sector states which get their mass from the Higgs vevs. The presence of these extra states leads to the fact that even as ∆ → 1, the DSSM does not reduce to the MSSM. In particular, the Higgs can naturally be heavier than the W -and Z-bosons. Perturbative gauge coupling unification, a large top quark Yukawa, and consistency with precision electroweak can all be maintained for ∆ close to unity. Moreover, such values of ∆ can naturally be obtained in string-motivated constructions. The quasi-hidden sector generically contains states charged under SU(5) GU T as well as gauge singlets, leading to a rich, albeit model-dependent, collider phenomenology.

Section: The Extra Statesmentioning

confidence: 83%

“…In this case, the top quark Yukawa can remain reasonably large, as it is close to being a marginal coupling. Further, when δ ≤ 0.1, perturbative gauge coupling unification is retained [5] (see also [18]). As we explain later, the regime 0.01 ≤ δ ≤ 0.1 is also favored by constraints from precision electroweak physics.…”

Section: Introductionmentioning

confidence: 98%

Electroweak symmetry breaking in the DSSM

Heckman

Kumar

Vafa

et al. 2012

“…(3.25) for which γ > 0. Thus, in addition to allowing for unification in High Scale SUSY, these F-theory corrections are another means of realising precision unification in the MSSM, distinct from existing mechanisms [73,[75][76][77][78][79][80][81].…”

Section: Parameterising the Precision Of Unificationmentioning

confidence: 99%

Precision unification and proton decay in F-theory GUTs with high scale supersymmetry

Hebecker¹,

Unwin

2014

Self Cite

F-theory GUTs provide a promising UV completion for models with approximate gauge coupling unification, such as the (non-supersymmetric) Standard Model. More specifically, if the superparters have masses well above the TeV scale, the resulting imperfection in unification can be accounted for by the, in principle calculable, classical F-theory correction at the high scale. In this paper we argue for the correct form of the F-theory corrections to unification, including KK mode loop effects. However, the price of compensating the imprecise unification in such High Scale SUSY models with F-theory corrections is that the GUT scale is lowered, potentially leading to a dangerously high proton decay rate from dimension-6 operators. We analyse the possibility of suppressing the decay rate by the localization of X, Y gauge bosons in higher dimensions. While this effect can be very strong for the zero modes, we find that in the simplest models of this type it is difficult to realize a significant suppression for higher modes (Landau levels). Notably, in the absence of substantial suppressions to the proton decay rate, the superpartners must be lighter than 100 TeV to satisfy proton decay constraints. We highlight that multiple correlated signals of proton decay could verify this scenario.

“…The issue of gauge coupling unification in the presence of VL fermions is not a new idea and it received a lot of attention in the literarture, both before the launch of the LHC [14,15,16,17,18,19,20,21,22,23], and after [24,25,26,27,28,10]. Similar analyses within the SUSY framework were performed as well [29,30,31,32,33,34,35,36]. In most of the former studies only particular types and a limited number of VL representations were considered.…”

Section: Introductionmentioning

confidence: 99%

Road map through the desert: unification with vector-like fermions

Kowalska

Kumar

2019

In light of null results from New Physics searches at the LHC, we look at unification of the gauge couplings as a model-building principle. As a first step, we consider extensions of the Standard Model with vector-like fermions. We present a comprehensive list of spectra that feature fermions in two distinct SU (3) C × SU (2) L × U (1) Y representations, in which precise gauge coupling unification is achieved. We derive upper and lower limits on vector-like masses from proton decay measurements, running of the strong gauge coupling, heavy stable charged particle searches, and electroweak precision tests. We demonstrate that due to a particular hierarchy among the mass parameters required by the unification condition, complementarity of various experimental strategies allows us to probe many of the successful scenarios up to at least 10 TeV.